* Risk aversion ebbs slightly after delay in US healthcare vote
* USD up as stocks firm and US yields rise after vote delay
* Uncertainty over Trump administration still limits USD rise
* Dollar/yen on track to lose more than 1 pct on the week
* Aussie hits 8-day low as iron ore prices decline (Updates throughout)
By Shinichi Saoshiro
TOKYO, March 24 (Reuters) - The dollar edged up against the yen and euro on Friday, pulling away from recent lows, but gains were capped as investors focused on a showdown between U.S. President Donald Trump and members of his own party over a new healthcare bill.
Trump warned House Republican lawmakers that he will leave Obamacare in place and move on to tax reform if they do not get behind new healthcare legislation and support it in a vote on Friday.
Postponement of the vote from Thursday initially knocked the dollar and stock markets, but the dollar was given breathing space as Treasury yields turned higher after Wall Street shares trimmed losses to close little changed.
Equities in Asia took heart and firmed on Friday, with Japan's Nikkei rising 1 percent.
"The dollar had been sold on the assumption that the healthcare bill would not pass, but some of those positions look to have been unwound. The market focus appears to have shifted to how Trump can pass the bill, from if he can push the bill through," said Bart Wakabayashi, branch manager for State Street Bank and Trust in Tokyo.
"U.S. yields are higher and it's not hard for dollar/yen to attract bids. It is often overlooked but the dollar continues to enjoy underlying support from widening U.S.-Japanese interest rate spreads."
The dollar was up 0.35 percent at 111.340 yen, pulling back from a four-month low of 110.620 struck overnight.
The U.S. currency was still on track for a 1.2 percent loss against its the yen this week, during which the safe-haven yen benefited from equity market volatility.
The yen has also gained from a scandal involving a land deal that has chipped away support for Prime Minister Shinzo Abe.
While that may appear counterintuitive, the yen has been a safe-haven of choice even when risk events originate domestically.
The currency rallied when a devastating earthquake struck Japan in March 2011 and triggered a nuclear disaster, prompting an intervention by Tokyo to arrest its surge.
The healthcare vote, which had been expected to be an early legislative win for Trump, is seen by investors as a litmus test for his ability to work with Congress and push through key policies such as tax reform and infrastructure spending.
"Even if the bill happens to be passed, any bounce by the dollar is likely to be limited. There are plenty of other issues Trump has to contend with going forward, such as tax reforms," said Ayako Sera, senior market economist at Sumitomo Mitsui Trust.
The dollar index against a basket of major currencies was up 0.2 percent at 99.941. It was on track to lose 0.35 percent this week, during which it stooped to a seven-week low of 99.547.
The euro slipped 0.2 percent to $1.0765. The common currency, which advanced to a seven-week peak of $1.0825 on Wednesday, was headed for a 0.3 percent weekly gain.
The pound was down 0.3 percent at $1.2490. It scaled a one-month high of $1.2532 overnight on upbeat British retail sales data.
The Australian dollar fell to an eight-day low of $0.7610 following a decline in the price of iron ore, the country's key export product. (Reporting by Shinichi Saoshiro; Editing by Eric Meijer)